Question

(1+tan24°)(1+tan21°)(1+tan23°)(1+tan22°)=4

Answer 1

remember the formula

(1+tan(A))(1+tan(B))=2

if A+B=45°

so pair 1st and second bracket

and pair 3 and 4th bracket

which will give you 2*2 = 4

try to proof above formula by urself using Tan(a+b) formula, it will help you making trignometry strong.

thankyou.